Localization and characteristics of atrial natriuretic peptide receptors in prenatal and postnatal rat brain.

We studied the expression of atrial natriuretic peptide (ANP) receptor subtypes during development in the rat forebrain, using quantitative autoradiography. Highest ANP binding was observed in the cortical neuroepithelium at embryonic day 17. Lower ANP binding was found in cingulate and frontal cortices at postnatal day 10, but none was detectable at 8 weeks of age. In the neuroepithelium of the embryonic rat, binding was displaced with a potency of rat ANP-(1-28) (rANP) > porcine type-C natriuretic peptide (pCNP-22) = rat ANP fragment C-ANP-(4-23) (rC-ANP-(4-23)) = rat brain natriuretic peptide (rBNP-32), different from that of any of the well-characterized (ANPA, ANPB, and ANPC) natriuretic peptide receptors. The present results support the hypothesis of a role for ANP during brain maturation and indicate that the ANP receptors highly expressed in the embryonic neuroepithelium may belong to a new ANP receptor subtype not yet characterized.